JPS596273A - Liquid crystal display element - Google Patents

Abstract

PURPOSE:To improve display quality, particularly contrast, visual angle characteristics, etc., by incorporating as a component of liq. crystal compsn. a colorless liq. crystal compd. contg. a particular six-membered ring in its molecular skeleton, in a time-sharing drive liq. crystal display element. CONSTITUTION:A liq. crystal layer is formed between two clear substrates in parallel to form an electrode on the surface of substrates in contact with the liq. crystal layer, providing an orientation controlling film of liq. crystal molecules on the surface of substrates in contact with the liq. crystal layer to compose a time-sharing drive liq. crystal display element. A colorless liq. crystal compd. (e.g., formula I or II) is incorporated in a liq. crystal compsn. as at least one component thereof to yield the intended liq. crystal display element, wherein said colorless liq. crystal compd. contains in the molecular skeleton one or more six-membered rings, at least one of which has two or more carbon atoms, at least one of which combines directly with a methylene group, which is at an end of a non-cyclic group, the terminal of which is an alkoxy group.

Description

[Detailed description of the invention]

The present invention relates to a liquid crystal display element, and more particularly to a time-divisionally driven liquid crystal display element suitable for matrix displays such as liquid crystal televisions, graphics, and displays. In a time-divisionally driven liquid crystal display element, there is a relationship between the effective voltage and the scanning duty ratio as shown in the following equation. (However, Vg is the effective voltage of the selected segment (segment to be lit), and vNS is the unselected segment (segment to be lit).
vo indicates the driving voltage, and N indicates the scanning duty ratio. Also a Fivr
It is N + 1. ) There is a problem in that the higher the scanning duty ratio, the more the effective magnetic pressure during one drive is reduced. In other words, the higher the time-division driving, the lower the display quality of the element, for example, the lower the contrast, the narrower the viewing angle, and other disadvantages. In order to solve these drawbacks, the thickness (d) of the liquid crystal layer and the refractive index anisotropy (Δn) of the liquid crystal layer should be controlled to appropriate values (Ai) pI , Phys , Let
t. 38(7), 497-499 (1981)). Especially Δ
It is said that n·d≧0.5 is good for improving contrast and viewing angle characteristics. However, the device in practical use is d-7
~10 μm, and Δn is 20.1. Furthermore, in terms of device yield, it is preferable that d be larger. Under these circumstances, there has been a strong demand for a liquid crystal display element with high display quality in which a liquid crystal layer is formed from a liquid crystal composition with a smaller Δn. An object of the present invention is to provide a time-division driven liquid crystal display element with improved display quality, particularly contrast and viewing angle characteristics. A small Δn that achieves the above objective is required for an element with a scanning duty ratio of 1/8 or less, particularly 1/16 or less. The present invention comprises a liquid crystal layer, two substrates sandwiching this layer and arranged parallel to each other, and electrodes and an alignment control film for aligning liquid crystal molecules formed on the liquid crystal layer side of each substrate. In a liquid crystal display element in which at least one of the substrates is a transparent substrate, the liquid crystal composition is characterized in that a liquid crystal composition that has been subjected to time-division driving is selected. This liquid crystal composition contains as at least one component (1) at least one 6-membered ring in the molecular skeleton, (11) at least one 6-membered ring has 2 or more carbon atoms, and (iii) a methylene group is directly bonded to at least one of the carbon atoms, (iv) the methylene group serves as one end of the acyclic group, and (■) the terminal group of the acyclic group is an alkoxy group; It contains a colorless liquid crystal compound. In particular, as an acyclic group, tcH
ztiOcyuH2-ya1 or fCH010し口1儒0
C4H21+t (n*''+1 is an integer from 1 to 8) is suitable. ri', t, unknown, ■ At the buttocks, the liquid crystalline compound I proboscis is
The term also includes compounds that exhibit a liquid crystal phase when mixed with other liquid crystal compounds, even if they do not exhibit a liquid crystal phase by themselves. ``Provision f'1: of (+) and (i+) in j11 is intended to ensure compatibility with other liquid crystal materials.
Examples of bases for fraudulent membership include the following:
coo-, -c-mi c-, -cti=c+t-. Cl1zCl-(z, CLIPO-, CH2N
It may be bonded with f-1- or a single bond. Also, alkyl groups, alkoxy groups, afur groups, anluoki/
group, arylkoxycarbonyl group, cyano group, nitro group,
-・Logen group, /・a genated argyl group, halogenated f
Lukoxy group or j CII 4' n60CHz arc C
LH2t or 1 or [-CHz-)-KO-(CFI2
) 甫0(, tH21゜1 (rl, m is an integer of 1 to 8, and t is an integer of 0 to 8). The liquid crystal composition of the present invention may be The nematic liquid crystal for this purpose can be any known liquid crystal material, such as MOL.Cryst, & Liq,Cryst, 63.
3-18 (1981) or Ed, h, y A.
l too, l(mets&F, l(, von Willise
r :Nonemissive Electroop
ticD 1sprays, p83-pH9 (197
5), P IenumPress, N, Y, & L
Compounds or derivatives described in Ondon can be used. Among these, compounds that are particularly effective in the present invention are compounds containing at least one self-cyclohexane ring or bicyclooctane term with a relatively small Δn, or compounds into which a fluorine atom is introduced. Incidentally, in the following formula, ILI is an alkyl group, p is an alkoxy group, and 几 and は are bicyclooctyl groups, and at least one kind of Schiff is used in the present invention.Of course, the parent liquid crystal used in the present invention is not limited to these nematic liquid crystal compounds. It may be composed only of liquid crystal compounds that satisfy each of the conditions (1) to (V) above. Furthermore, an optically active substance may be added as necessary. Next, V of the liquid crystal thin material satisfying the above conditions (1) to (V)
/l] and its synthesis method will be explained. In the same formula, R3 and IL4 each represent an alkyl group. Manufacturing method and physical properties of colorless liquid crystal compound>; Lithium aluminum hydride (Ll[:AtH4]
) 31.2 g and tetrahydrofuran (6) 20
Add oml and suspend. 1 t of the solution was added dropwise to the solution while stirring under water cooling, and after the dropwise addition was completed, stirring was further continued at room temperature for 2 hours. Next, this reaction solution was poured into 3 t of diluted hydrochloric acid and stirred to separate the organic layer.
Add 100 ml of OH) and add metal sodium Ck to this.
hOCsHr (sample 1) was obtained. Sample 10 elemental analysis values (C; 33.43%, H; 11.
30%) is the calculated molecular weight of Cz+H3xQ (C; 83
゜38%, H: 11.33%). In addition, in the infrared absorption spectrum of sample 1, absorption of ether bond appears at 1100C1n-'. From both facts and the relationship with the raw material compound, it was confirmed that Sample 1 was a liquid crystal compound of the above formula. Table 1 shows the phase transition temperatures of Sample 1 and other samples obtained by a manufacturing method similar to Sample 1. Manufacturing method and physical properties of colorless liquid crystal compound's proboscis> (Sample 17
) is obtained. The elemental analysis values for sample 170 (Ci 83.30%, II. 11.42%) were in good agreement with the molecular weight calculation values for 02114s40. In addition, in the infrared absorption spectrum of sample 17, absorption of ether bond appears at 1110 m-1. Based on both facts and the raw material compound, it was confirmed that Sample 17 was a liquid crystal compound of the above formula. Table 2 shows the phase transition temperatures of Sample 17 and other samples obtained by a manufacturing method similar to Sample 17. Manufacturing method and physical properties of colorless liquid crystal compound: and Cz Hs
Add 600 ml of OH and stir while cooling with water. After that, 17.1 g of sodium borohydride (Na(,13H<J)
5 small portions were added and stirred at room temperature for 2 hours. Next, 2501111 of water was added and stirred to distill off C2Hs (JH. Then, 235.7 g of 5ucz was put into another flask, 32 g of -CH20H was added, and the mixture was stirred for 4 hours under reflux. This reaction solution was poured into water and 7 After separating the filter layer, add 100 ml of Os Hy OH and Na014 to another flask.
g was added thereto, and the temperature was raised to 1 f with a flow of I2, and the mixture was stirred for the above-mentioned 4 hours. When this reaction solution is poured into water and extracted with (CzHs)zO oil, a colorless liquid crystal compound is obtained. Elemental analysis value of sample 27 (C; 79.13%, H; 8.
89%, N; 5.31%) is the calculated molecular weight of C+7H1tNO ((: ; 79.33%, l-1; 9.0
1%, N: 5.44%). In addition, sample 2
In the infrared absorption spectrum of Sample 7, absorption of /ano group appears at 2220/771-' and absorption of ether bond appears at 1115 tyn-''. From both facts and the relationship with the raw material compound, sample 27 is a liquid crystal compound of the above formula. It was confirmed that Sample 27 had a phase transition temperature of C-I; 21C, N-I;
It was a -7oC monotropic liquid crystal. <General formula I, too? C〈■) 8CH201 also 4 Manufacturing method and physical properties of colorless liquid crystalline compound〉; g and C
Add 600 ml of 2T-(80H) to the water-cooled and stirred solution. After adding 17.1 g of Na[BH41] little by little, stirring is continued at room temperature for 2 hours. Then acetic acid IQm
Add A', add 2 t of water, and heat and reflux the (Cdb)*0 extraction for 4 hours. Pour this reaction solution into water to obtain Cs1-. bol-110
4 g of NaO was dissolved in 0 ml and heated and stirred for a period of time. When this reaction solution is poured into water and subjected to CzHshO extraction, a colorless liquid crystal compound is obtained. Elemental analysis value of sample 2B (C; 34.83%) (;9.
73%) is the calculated molecular weight of CzlHzsO (C; 85
．． 08% and Hi 9.52%. In addition, in the infrared absorption spectrum of sample 28, absorption of ether bonds appears at 1100 cm-'. From both facts and the relationship with the raw material compound, it was confirmed that Sample 28 was a liquid crystal compound of the above formula. Table 3 shows the phase transition temperatures of Sample, M2S, and other samples obtained by a manufacturing method similar to Sample 28. Table 3 Trial 1 [31 element system analysis value < C near 6.05%, 11゜8
．． 85%, N: 9.45';'o)llj
: Molecule of Cl91hsNzO...double calculation value (C; 76
．． 47%, H: 8.78%, N: 9.38%. From both facts and the relationship with the raw material compound, it was confirmed that Sample 31 was a liquid crystalline compound of the above formula. C-I; 51tl'. General formula It3-(p■←UG下ΣBeklisuC112o1
(Production method of colorless liquid crystal compound represented by , 4;
1; 8.43%) is the molecular weight of C25HO ^1゛#, I+
It was in good agreement with N (C; 87.16%, II; 8.19%). In addition, the infrared absorption spectrum of sample 33 is 110
Absorption of ether bonds appears at 0 cm-'. From both facts and the relationship with the raw material compound, sample 33 is 1ffl of Urimani style.
It was confirmed that it is a crystalline compound. The phase transition temperature of sample 33 is c-s, 233[, s-
N i 240iC, N −I is 245C. Method for producing liquid crystalline compounds and '1-button; C1hOH60
After 9611q, 20 g of KN a was dissolved and stirred, heated to reflux, and 120 g of r-bromopropylbenzene was added dropwise. After 9611q, the reaction solution was diluted to give glopylbenzene. The boiling point of this chemical substance is 96-98tZ'/
15m+nHg. C1bC121,5 inside, ktct3195 g
and 100 g of γ-methoxy7-propylbenzene were added, and the mixture was stirred and cooled on ice. This is added to acetyl chloride (Cl-13
0 Oct) 79 g was added dropwise little by little, and stirring was continued for 6 hours while cooling with water. After confirming that the generation of hydrogen chloride gas (HCt) has stopped, 1 part of diluted sulfuric acid is poured into the reaction solution, and the HCt is heated.
The H2Cl2 layer is separated, CH2Cl2 is distilled off, and then distilled under reduced pressure to obtain 4-(γ-methoxyglobil)-acetophenone. The boiling point of this compound is 94-95? :
'10.3In 1g resistance. 4-(γ-methogiciglovir)-acetopheno 767
g and 620 ml of 88% anhydride (HCOOH) were mixed and stirred, and then acetic anhydride (CHs (0) 2
0) 310 ntl, concentrated sulfur [4 mJ, 35% hydrogen peroxide solution 110 ml, in that order. After heating to 4 degrees (40-50C) and pressing for 8 hours, the reaction solution was poured into water. After completely extracting the separated oil and distilling off the solvent, CHsOH1
00ml of 2N caustic soda aqueous solution 250M was added and heated under reflux for 2 hours. After cooling, the oil is separated by acidifying the reaction solution with hydrochloric acid. This gives 4-(γ-methoxyglopyl)-phenol. The boiling point of this compound is 100-108 tT/10 mmHg. After washing with 4-(γ-methoxy/clovir)-phenol, 14 g of trans-pentylcyclohexylcarboxylic acid chloride was added dropwise with stirring, and stirring was continued at room temperature for 3 hours. The reaction solution was poured into water and old crystallized using C1bCOCH1. The infrared absorption spectrum of the compound obtained by this method was 17
It shows absorption of ester bond at 50 cm-', 1120/
1771-' shows absorption of ether bond. Also, IA
(, If (in the spectrum, (t) the molecular ion peak is m
/ Appears in e346. From both facts and the relationship with the original 1F compound, the compound synthesized here has a melting point of 4-(r-methokinopropylphenyllo sample 34) of 42C1, a phase transition temperature of 1 -N;
It was C. In the same manner, a colorless liquid crystal compound represented by the general formula 11J can be produced by changing the number of carbon atoms 'f' in the starting material compounds 'It' and Jj' or by changing the number of q. As mentioned above, the compound represented by this general formula can be synthesized using Williamson's ether synthesis method, Friedel-Crafts reaction, and Bayer-Villiger method. The manufacturing method based on combination is the easiest. In the sister example of the present application to be described later, the compound shown in Table 4, which was produced according to Sample 34 above, is also used. Table 4 Manufacturing method and physical properties of the compound; In a flask, 2-octanone (CH3 (CH.)s
600g of C(X3m) and tcrt-butanol ((
Cf(3)3(OH))500gs and 3
0% KOH/CHsOH solution 3. Mix with g and stir on ice-cold F. Add acrylonitrile (C112) to this solution while keeping the temperature below 5C.
=CHCN) 375 g (CH3) s C0I-
Drop the solution dissolved in 1400 g. After the drop is finished,
Stirring was continued for an additional hour, and then diluted hydrochloric acid was added to the reaction solution to make it neutral. The precipitated salt is filtered off and the residue is distilled under reduced pressure to obtain 3-acetyl-1,5-zineano-3-pentylpentane. 232 g of this reaction product was mixed with 20% N 2.01-1
The mixture was poured into 1,400 g of an aqueous solution and heated and stirred for 8 hours. Next, it is made weakly acidic with dilute hydrochloric acid, and chloroform (CHCls
) Extract. When the solvent is distilled off, 4-acetyl-4-
Pentylpentanedioic acid is obtained. 130 g of this reaction product was converted into (CHsC(J)+07
4-acetyl-4-bentylcyclohexanone No. 1 is obtained by dissolving in 50 ml of 1K, heating and flushing for 3 hours, and then distilling under reduced pressure. 70 g of this reaction product was mixed with 600 g of 10% KOH aqueous solution.
ml and heated under reflux for 5 hours. After cooling, the mixture is neutralized with dilute hydrochloric acid and extracted with 20% (CaH5). If (CzlIs) 20 is distilled off, 1-hydroxy-4-pentyl-3-bicyclo(2,2,2) mectanone is obtained. 21 g of this reaction product is dissolved in 130 ml of Nl2 Nl2 and heated under reflux for 5 hours. After cooling, add 29g of KOH and 180ml of 110(CH2)20(CH2hOH) and heat to 230-240C. At this time, N Hz
N H2 is distilled off, the pig iron whose generation of nitrogen gas (N2) has stopped, and cold water (C2H5) 20 times are extracted separately. (Cd(shO is distilled off, l-hydroxy-
4-pentylbicyclo(2,2,2)octa/ is obtained. 20 g of this reaction product was added to a mixed solution of 160 g of hydrobromic acid and 40 g of concentrated sulfuric acid, and heated under reflux for 4 hours. After cooling, pressurize into 50 Inl of water, (C21-15)
After performing zO extraction and distilling off (C2H3) 20, distillation under reduced pressure yields l-bromo-4-pentylbicyclo(2,2
,2) Octane is obtained. In another flask (#50Ml of sulfuric acid and mercury sulfate (H, g)
1.3 g of SO4) was mixed with sweat and cooled to 5C, and the above 1-p(Jmo4-pentylbicyclo(
2,2,2) Octay3g n-C5Ht4 solution 5m
Add l. Add 98% HCOOHl ml to this.
Add little by little. After gas generation has stopped, the reaction solution is added to 600 ml of ice water to precipitate crystals. When the crystals are filtered off, 1-carboxy-4-pentylbicyclo(2,2,2)octane is obtained. 3. of this reaction product. Add Og to 230 ml of SOCt and continue stirring for 8 hours while maintaining the temperature at 60C. When this is distilled, hydrogen bromide gas (,14
B r ) for 2 hours. After that, stirring was continued for 2 hours and 4- was obtained by distillation. The boiling point of this compound is 12
5-126C/15 mmHg. Furthermore, in another flask, add N to 300 ml of Ca Ib OH.
5g of a was dissolved, and while refluxing, the refluxed product was poured into ice water, and the separated oil layer was extracted with (CzllsO)+0. The extract is dehydrated, converted to 4-(α-propoxymethyl)phenol, and refluxed for 3 hours. The reaction product was washed with water, ((, zl
Excluding lshO and distilling the residue into the rainbow, the target product] 4-
(α-propoxymethyl)phenyl-4/-pentylbicyclo(2,2,2)octane sample 43) is obtained. The infrared absorption spectrum of sample 43 shows ester absorption at 17500n-' and ether absorption at 1100Crr1-'. In the mass spectrum of sample 43, a molecular ion peak appears at mle372. Elemental analysis values (
C; 77.41%, 14; 9.71%) and C2411
Calculated molecular weight of 3703 (C; 77.38%l Hi
9.74%), which showed good agreement. From these facts and the relationship between the raw material compounds, it was confirmed that sample 43 had the liquid crystallinity of the above formula. In addition, sample 43 is N-1; 24.0
．． CN; (21,0). A liquid crystal compound corresponding to the above general formula is produced according to Sample 43. That is, first, 1 is also s ClI2
C■J 2 with basic strip 1/l”F on C0CHs
= Get CHCN as Inaiai. The cyanide group is then hydrolyzed to a carboxyl group using an alkali, and the bicyclooctatool is sequentially converted to N1 by heating in the presence of a (CHsCO)20 alkali.
By reduction to 12 N H2 and reaction with acidified formic acid in a basic medium, the desired product is obtained. It was. Sample 44 is N-1; 62.0XC-N: (5
6,0) was rare. <Example 1>; Now, the final product of the liquid crystalline compound for an element of the present invention described above was prepared as nematic liquid crystal (81) E-7 manufactured by Company H. Abb manufactured by Atago Co., Ltd.
Δn was measured with an e-refractometer at λ=589 nm. The results are shown in Table 6 along with comparison Vll. The comparison results were obtained by adding each of the individual products shown in Table 5 to the above E-7 liquid crystal under exactly the same conditions as the liquid crystal compound for the device of the present invention. Table 5 Table 6 It can be seen from the above that the liquid crystalline compound for devices of the present invention has the following characteristics. (a) A liquid crystal compound of the present invention in which the acyclic group satisfies the above conditions (ii+) to (V) lowers the Δ0 of the liquid crystal composition compared to a comparative sample having an acyclic group that does not satisfy the above conditions (ii+) to (V). (
However, compounds with the same skeleton are compared. ) (b) The above tendency (a) is persistent in alicyclic compounds. (C) The length of the methylene chain in the acyclic group has a small effect on Δn. <Example 2>; Next, the Δn of the liquid crystal compound for an element of the present invention and a comparative sample will be compared individually. The chemical compound of Sample 5 and the compound of Comparative Sample B were added to a phenylcyclohexane liquid crystal (Merck ZLI-1132) from 1 to 5.
When Δn was measured and extrapolated to 100%, it was found that the compound of Sample 5 had an Δn of 0.03, and the compound of Comparative Sample B had an Δn of 0.07. Similarly, when comparing Sample 35 and Comparative Sample I individually,
The former showed Δn = 0.035, and the latter showed Δn = (1,09. The above Δn has a value of 10 to 50% /J
Since additivity is established at ll 4t, it was found that the liquid crystalline compound for an element of the present invention has a significantly smaller Δn than the comparative sample compound even when used alone. The amount d of the compound of the present invention in the liquid crystal composition is not particularly limited, but it is preferably added in an amount of 10% or more because the effect of Δrl is achieved as additivity as described above. EXAMPLE After a polyimide sample was placed on a transparent electrode substrate and rubbed, a reflective TN (TWistedNem) with a gap of 10 μm and a twist angle of 80° was prepared.
atxc) The device was exploded, and the liquid crystal compositions (A,) to (F) were encapsulated. n, m, t: All blue molar mixture n, m: All equimolar mixture ((),) ZI, i 1415 (Merck & Co.)
100% Δn −-0, 1, 4 o, ITI: All equimolar mixture (l:)
E-7 (8811 companies (UK)) 100% Δn
= 0.21 (1”) Example 20 100%
Δn=0.15 The above liquid crystal element was time-divisionally driven with a scanning duty ratio of 1:65.6, and the maximum contrast (ratio of reflectance at selected points and non-selected points) at a viewing angle of 20° was determined. However, I obtained the following results. Note that the angle of the incident light is 0° with respect to the normal to the element surface. Table 7 Table 7 shows that the smaller Δn is, the better the maximum contrast becomes. In addition, in all six cases, Δ is applied to the comparison column.
n is small, the maximum contrast is vague, and υether compound is an excellent liquid crystal that provides good contrast despite the high time-division drive with a scanning duty ratio of 1:32. Note that there are currently no commercially available liquid crystal display devices with a scanning duty of 1:65.6. Example 4: Similar to Example 3, the viewing angle was set to 30°. When the angle was changed to 40°, the results shown in Table 8 below were obtained. Table 8 Δ

It can be seen that the present invention with a small value of [1] has good contrast over a wide viewing angle range. Example 5>; When the same measurements as in Example 3 were made with the scanning duty ratio of 1:32.8, the results shown in Table 9 were obtained. Table 9 The above results show that the display elements using the liquid crystal composition of the present invention have good maximum contrast over a wide viewing angle even when the scanning duty ratio is 32.8. The tendency for the contrast to improve according to Examples 3 to 5 is more pronounced as the scanning duty ratio becomes higher and Δn becomes smaller, but it is currently unclear whether this is consistent with the literature described in the text, and Experimental data similar to this example is also not found. In the actual flight example, the present invention was shown in a high time division drive where the effect is particularly remarkable, but it is clear that the present invention is also effective in a time division drive with a small duty ratio. It is limited by the Niu-needy ratio and there are many 0 things, - Nii, 1 brother', llJshi/Konocho detour, I (Jyoakeyo) Shibai/Jteme 1] I generation ,'[, ynico/Tonos IFrjikaku custom-made same as the above, tAtsuta time cut, 44 pieces, tlE product) Juvenile fruit 546 which is said to have a long spittle f.

Claims (1)

[Claims] 1. A liquid crystal layer formed by (I′f, crystal composition/rostrum),
two substrates sandwiching the ak crystal layer and arranged parallel to each other, at least one of which is transparent; and an F1 potential pole formed on the surface of each substrate in contact with the liquid crystal layer; In a time-divisionally driven liquid crystal display element comprising an alignment control film formed on a surface in contact with an originating crystal layer to control the alignment of liquid crystal molecules, at least one component of the liquid crystal composition comprises one of the following: A colorless liquid crystal compound satisfying the following conditions: 4. A liquid crystal display element characterized by: (1) contains at least one 6-membered group in the molecular skeleton, (11) at least one of the 6-membered groups has two or more carbon atoms, and (iii) at least one of the carbon atoms has a methylene group. (1v) the methylene group serves as one end of an acyclic group, and (V) the terminal group of the acyclic group is an alkoke group. 2. If the acyclic group is +C1h QC, H button or l (however,
n and m represent integers of 1 to 8. ) The Rk crystal display element according to claim 1, characterized in that the Rk crystal display element is represented by: